Local Alpha1‐Antitrypsin Accelerates the Healing of Tympanic Membrane Perforation in Mice

Background Most tympanic membrane (TM) perforations heal spontaneously, but 10%–20% remain chronic and might lead to impaired hearing and recurrent middle ear infections. Alpha1‐antitrypsin (AAT) is a circulating tissue‐protective protein that is elevated under inflammatory conditions and is currently indicated for genetic AAT deficiency. Recently, AAT has been shown to promote tissue remodeling and inflammatory resolution. Objective This study aimed to examine the effects of local clinical‐grade AAT treatment on tissue repair in a mouse model of acute traumatic TM perforation. Methods Wild‐type mice underwent unilateral TM perforation and were either left untreated or treated locally with human AAT (9 × 10−3 mL at 20 mg/mL on days 0, 1, and 2; n = 15/group). The perforations were evaluated macroscopically on a serial basis. Mice were sacrificed on various days post‐injury, and TMs were excised for gene analysis by RT‐PCR. Results There were no adverse reactions in hAAT‐treated ears throughout the study period. Compared with untreated animals, TM closure occurred earlier in the treated group (days until full closure, median: 4 and 9, respectively). According to gene expression analysis, VEGF, TGFβ, and collagen‐5A1 were induced earlier in AAT‐treated mice (day 4–5 compared with day 9). Additionally, IL‐10 expression levels were higher and IL‐6 levels were lower in treated versus untreated mice. Conclusion A local tissue environment rich in AAT promotes early tissue repair in a perforated TM model both macroscopically and molecularly. Studies are underway to examine TM functionality and recombinant AAT formulations for micro‐dosing in the format of a single local application. Level of Evidence NA Laryngoscope, 134:3802–3806, 2024 In the current investigation, the application of alpha1‐antitrypsin (AAT) to mice with acute tympanic membrane perforation accelerated the healing process, leading to earlier expression of growth factors such as VEGF, TGFβ, and collagen‐5A1. AAT also increased IL‐10 expression levels and decreased IL‐6 levels in the treated mice. These findings suggest that AAT may promote tissue repair in a mouse model of acute traumatic TM perforation and support its potential as a therapeutic agent for accelerating wound healing.